Whitehall sources also claimed Mr Salmond had been forced to name the autumn 2014 date after the intervention of Prime Minister David Cameron at the weekend.

Ministers said they welcomed the SNP leader’s “engagement” following eight months of ducking questions over the referendum since the SNP’s election victory last May.

This is the most important decision in Scotland for 300 years

First Minister Alex Salmond

Earlier, Scottish Secretary Michael Moore told MPs the Coalition was willing to devolve authority for Holyrood to conduct its own poll so long as it was “legal, decisive and fair”.

But despite being told he faced the prospect of years of legal conflict in the courts, Mr Salmond resisted UK Government demands to set an early date.

Instead he retaliated by announcing his own proposals with a target date close to St Andrew’s Day, November 30, which falls on a Sunday that year.

It is thought Nationalists are keen to capitalise on the 700th anniversary of the Battle of Bannockburn in June, the Commonwealth Games in Glasgow in July and August and the Ryder Cup at Gleneagles in September.

Mr Salmond said he would only accept the offer of a deal to legally authorise the referendum if it was unconditional.

“This is the most important decision in Scotland for 300 years,” he said. “The date will allow people to hear all of the arguments. Autumn 2014 is the date which offers the opportunity for Scotland to have a considered referendum.”

The SNP administration insist their plans would be legal, but their insistence on holding their own referendum will almost certainly lead to a legal challenge by Westminster through the UK Supreme Court.

Once Westminster issues permission to hold a referendum – a Section 30 order approved by both Houses and Holyrood – it could be held in a year to 18 months, well before Mr Salmond’s chosen date.

But Mr Salmond added: “We’ve got nothing against the Section 30 proposals, but we are not going to have it with strings attached.

“We won’t have Westminster pulling the strings. I think the Westminster parties have got to start understanding – all Westminster politicians – that this has to be a referendum made, built, and run in Scotland.”

A spokesman for the First Minister said the referendum would be held in 2014, regardless of Westminster’s “attempts to interfere”.

He insisted the Scottish Government’s own legal advice was that it was within Holyrood’s powers to hold a referendum, the Bill would be published next January and consultation would be launched in around two weeks.

Under Westminster’s proposals now out for consultation there would be a single question – Yes or No on remaining in the UK.

The SNP favour a second question, on full fiscal powers or “devo max”, a fallback position if Scots reject full independence, which is highly likely.

She added: “It is also rather sad that a First Minister of Scotland keeps his plans for the constitutional future of our nation secret, doesn’t tell the Scottish Parliament, but goes on TV because a debate at Westminster might keep him out the headlines. We deserve better.”

Tory leader Ruth Davidson said: “At last Alex Salmond has been forced to give a date. Decisive action by the UK Government has forced his hand.

“We can discuss times and dates but the key issues are what is the question and who is the referee? We need a single, decisive question and we need the Electoral Commission, as an independent arbiter, to oversee such a historic vote.”

Scottish Lib Dem leader Willie Rennie said: “Announcing autumn 2014 as high noon in the fight to protect Scotland’s future as part of the UK family doesn’t address the issue of ensuring the Scottish people decide the outcome, not the courts.”

Earlier, Mr Moore told the Commons: “It is essential that the referendum is legal, fair and decisive. We have been clear that we will not stand in the way of a referendum on independence. But neither will we stand on the sidelines and let uncertainty continue.”